Silicon modified vinyl acetate ethylene copolymers

Abstract

This disclosure relates to silicon modified vinyl acetate ethylene copolymers and to emulsions and articles of manufacture based on the same.

1 .- 20 . (canceled) 
     
     
         21 . A method of polymerizing a silicon modified vinyl acetate ethylene copolymer, the method comprising:
 forming a copolymer comprising:   a. vinyl acetate;   b. ethylene; and   c. a silicon compound of Formula (I)   
       
         
           
           
               
               
           
         
       
       where,
 R 1  is a terminally unsaturated alkenyl radical; and 
 R 2 , R 3 , and R 4  are each independently selected from the group consisting of H, alkyl, substituted alkyl, heteroalkyl, substituted heteroalkyl, cyclyl, substituted cyclyl, heterocyclyl, substituted heterocyclyl, aryl, substituted aryl, heteroaryl, and substituted heteroaryl; 
 comprising the steps of: 
 contacting an initial charge of at least 50% of the total vinyl acetate units in the polymerization method with ethylene units; 
 performing the contacting step in the absence of the silicon compound, and initiating polymerization of the vinyl acetate-ethylene copolymer in the absence of the silicon compound; 
 thereafter, feeding remaining amounts of vinyl acetate units together with the silicon compound as a feed to the initiated vinyl acetate-ethylene copolymer polymerization; and 
 continuing polymerization until a silicon modified vinyl acetate ethylene copolymer is formed. 
 
     
     
         22 . The method of  claim 21 , wherein each of the step of contacting and the step of feeding are conducted in the presence of an emulsifier. 
     
     
         23 . The method of  claim 22 , further comprising conducting polymerization under agitation imparted by an impeller. 
     
     
         24 . The method of  claim 21 , wherein the step of continuing polymerization is conducted until a silicon modified vinyl acetate copolymer having a water solubility in the range of 0.9 to 1.85 wt. % at about 25° C. is obtained. 
     
     
         25 . The method of  claim 21 , wherein the step of continuing polymerization is conducted until a silicon modified vinyl acetate copolymer having a number average molecular weight (Mn) of 24,000 to 35,000 is obtained. 
     
     
         26 . The method of  claim 21 , wherein the step of continuing polymerization is conducted until a dried sample of the silicon modified vinyl acetate copolymer has an elongation at break in the range of 715 to 805%. 
     
     
         27 . The method of  claim 21 , wherein the amount of silicon compound relative to the amount of vinyl acetate reactant is in the range of 0.1 to 5.0 wt. % 
     
     
         28 . The method of  claim 27 , wherein the silicon compound is at least one selected from the group consisting of vinyltrimethoxysilane (VTMO), vinyltriethoxysilane (VTEO), γ-methacryloxypropyltrimethoxysilane (MEMO), and vinyltris(2-methoxyethoxy)silane (VTMOEO). 
     
     
         29 . The method of  claim 21 , including the step of deriving at least one of the vinyl acetate units and ethylene units from at least one selected from the group consisting of monomers, oligomers, and precursors thereof. 
     
     
         30 . The method of  claim 21 , wherein the step of continuing polymerization is conducted until a silicon modified vinyl acetate copolymer having an ethylene:vinyl acetate ratio 0.25:1˜0.40:1 is formed. 
     
     
         31 . The method of  claim 23 , wherein the impeller is a Marine impeller and the silicon compound is vinyltrimethoxysilane (VTMO). 
     
     
         32 . The method of  claim 23 , further comprising adjusting the impeller speed in the range of 250 to 300 revolutions per minute (rpm). 
     
     
         33 . The method of  claim 23 , wherein the impeller is an Anchor-type impeller and further comprising the step of setting the impeller speed to 250 revolutions per minute (RPM). 
     
     
         34 . The method of  claim 21 , further comprising, after the silicon modified vinyl acetate copolymer is formed, performing the step of adding the silicon modified vinyl acetate copolymer in aqueous form to at least one cement;
 wherein a film of the aqueous silicon modified vinyl acetate, when dried, has an improved elongation; and   wherein whitening of the cement is reduced.   
     
     
         35 . A method of polymerizing a silicon modified vinyl acetate ethylene copolymer, the method comprising:
 forming a vinyl acetate-ethylene copolymer by contacting an initial charge of vinyl acetate reactant and ethylene reactant in the presence of a polymerization initiator at a temperature in the range of 60° C. to 90° C., but in the absence of any silicon compound; and thereafter,   introducing a feed of
 a silicon compound selected from the group consisting of vinyltrimethoxysilane (VTMO), vinyltriethoxysilane (VTEO), 
   γ-methacryloxypropyltrimethoxysilane (MEMO), and vinyltris(2-methoxyethoxy)silane (VTMOEO); into the initiated vinyl acetate-ethylene copolymer polymerization;   the feed of the silicon compound occurring in the presence or absence of any additional vinyl acetate feed; and   continuing the polymerization until a silicon modified vinyl acetate-ethylene copolymer having a number average molecular weight (Mn) in the range of 24,000 to 35,000, a water solubility in the range of 0.9 to 1.85 wt. % at about 25° C., and an elongation at break in the range of 715 to 805%, is obtained.   
     
     
         36 . The method of  claim 35 , wherein at least 50 wt. % of the total vinyl acetate reactant in the polymerization process is present in the initial charge. 
     
     
         37 . The method of  claim 35 , wherein the silicon compound is present in an amount of 0.1 to 5 wt. %, based on the weight of the vinyl acetate and ethylene reactants. 
     
     
         38 . The method of  claim 37 , wherein the vinyl acetate reactant is at least one selected from the group consisting of monomers, oligomers and precursors of vinyl acetate. 
     
     
         39 . The method of  claim 35 , further comprising performing the polymerization in an emulsion, wherein the emulsion is agitated by one impeller selected from the group consisting of Marine type and Anchor-type impellers, and setting the operating speed of the one impeller in the range of 250 to 300 revolutions per minute (rpm). 
     
     
         40 . A silicon modified vinyl acetate-ethylene copolymer produced by the process of  claim 21 . 
     
     
         41 . A silicon modified vinyl acetate-ethylene copolymer produced by the process of  claim 35 .